Strange connections

southern resident killer whales

Southern resident killer whales on the move/NOAA photo

The littlest of Pacific salmon is once again demonstrating big power in the ecosystem of the northern ocean.


Scientists have found evidence that appears to link pink salmon abundance to high death rates and low birth rates in critically endangered southern resident killer whales that inhabit the waters of Washington State, British Columbia, Canada; and Southeast Alaska.

A peer-reviewed study published earlier this month in Marine Ecology Progress Series concludes pink salmon abundance is the only likely explanation for even-year spikes in deaths, along with declines in births, that now characterize the small and struggling whale population shrinking toward extinction.

The connection is not what you might at first suspect: starving whales in years when pinks are scarce followed by healthier periods when pinks are abundant.

Instead, in this case, the situation is exactly the opposite. The whales suffer most when pinks are abundant and do better when they are scarce. The situation appears to have a lot to do with diet.

The fish-eating whales seldom prey on three- to five-pound pinks. The salmon on which they are largely dependent are Chinook – kings as Alaskans are prone to call them – five to 10 times bigger than pinks and sometimes more.

Despite any direct predator-prey relationship between pinks and the endangered killer whales, Seattle scientist Greg Ruggerone; Auke Bay, Alaska scientist Gus van Vliet; and colleagues from the University of Alaska Fairbanks and the Alaska Department of Fish and Game, found a hard to ignore link between the two species.

“From 1998−2017, mortality of newborn and older whales was 3.6 times higher (61 versus 17 whales) and successful births 50 percent lower (16 versus 32 whales) in even years than in odd years as the population decreased from 92 to only 76 whales,” their study reported. “Percent mortality was 3.1 times higher in even years during the recent 20-year period of population decline than during an earlier 22-year period (1976−1997) of population increase and relative high abundance, whereas mortality in recent odd years was 43 percent lower.”

“We have identified a previously unknown odd/even-year factor linked significantly to survival and low birth rate of southern resident killer whales (SRKW),” they concluded. “None of the purported factors of SRKW decline (Chinook salmon abundance, toxic contaminants, ship noise) can directly explain the biennial demographic pattern. In contrast, the extreme biennial pattern in abundance of pink salmon, coupled with the known or suspected effects they have on other species and ecosystem processes elsewhere in the North Pacific, is consistent with the demographic pattern observed in SRKWs.”

Lost in the crowd

The scientists suggested two different theories that might explain the linkage between pinks and whale survival. One is pretty simple; big schools of pink salmon simply get in the way of the whales.

“One hypothesis…is that highly abundant odd-year pink salmon interfere with the ability of whales to feed on co-migrating summer and early fall Chinook salmon in the Salish Sea during a two-month period when the (whale) are highly dependent on the already depleted Chinook salmon.”

Chinook salmon runs through the Pacific Northwest have struggled in recent years as ocean conditions have turned in favor of some Alaska salmon in particular – sockeye from the state’s Bristol Bay have been returning in record-breaking numbers – and pink salmon in general. 

Pink salmon in the Salish Sea – a 6,500-square-mile body of water stretching north from southern Puget Sound in Washington State to Desolation Sound in British Columbia, Canada – are now about “50 times more abundant than the co-migrating Chinook salmon in this area,” the Ruggerone study notes. “Reduced foraging efficiency of the whales would lower their nutritional status, which would be expressed in the following even year because these large mammals have a strong physiological buffering capacity.

“Furthermore, the finding that lower nutritional status of southern resident killer whales is linked to higher rates of miscarriages and mortalities of newborns supports our observation of higher newborn mortality in even years.”

The southern resident killer whales largely spend the summer and fall in the Salish Sea feeding on salmon, and then range south as far as Monterey Bay, Calif. and as far north as the Panhandle in their winter and spring searches for food, according to the National Oceanic and Atmospheric Administration.  

The dependence of the southern resident whales on Chinook salmon has long been known. A member of the Washington Fish and Wildlife Commission earlier this year called for stocking 50 million hatchery king salmon smolt in Puget Sound in hopes of providing more food for the hungry whales.

“These would be released in carefully selected areas where negative impacts to the genetic strains of wild Chinook salmon would be minimized and using genetic strains for hatchery production that have migration patterns that take them to the areas where the killer whales are so they can feed on them,” Don McIsaac, a former member of the Pacific Fisheries Commission, said on ESPN’s Outdoor Line in Seattle in August. 

The whales are tangled in both the practicalities and politics of Pacific Northwest Chinook management. There are struggles to figure out how to get adult salmon upriver past dams and debate on how to pass young salmon back downstream without all being eaten by predators in reservoirs or churned into salmon burger in electricity-generating turbines.

There are struggles over the allocation of the small allowable catch of returning fish between wild predators, Indian tribes, anglers and commercial fishermen. And there are disagreements on whether hatcheries are a good thing for the fish or a bad thing for the fish.

Hatchery stocking has been reduced in recent years amid concerns one consequence of hatcheries is fewer wild Chinook, but the hatchery fish increasingly appear vital to the survival of the southern resident whales.

The whales could drive a change in hatchery policies, Karina Brown reported for The Courthouse News Service in September, writing that “in Puget Sound, about 80 percent of the salmon returning from the Pacific are hatchery fish.

“The government appears poised to increase hatchery Chinook by about 25 million per year. In a survey of members of the Southern Resident Killer Whale Task Force compiled Aug. 23, the top three recommendations out of 60 were to increase hatchery Chinook, accelerate habitat restoration for Chinook and require small boats to stop using echo sounders.”

Washington state Gov. Jay Inslee has proposed the state spend more than $1 billion over the next several years to try to help save the whales. Most of the money would go toward habitat restoration, but there’s almost $100 million for hatcheries in the proposal, the Chinook Observer reported.

“An adult male orca needs about 325 pounds of Chinook salmon every day,” its story added. “The problem is that the number of Chinook available in the inland seas from southeast Alaska to southern Puget Sound and along the west coast to the Columbia River has…been in decline.”

Complicated picture

While it is possible pink salmon are preventing the orcas from finding the Chinooks they need, the latest study says, there is also a possibility the bounty of pinks is in some way helping keep the whales from disappearing.

“An alternative hypothesis is that pink salmon enhance the ability of whales to feed, resulting in lower mortality in odd years of high pink salmon
abundance,” the scientists wrote.

The high death rate and low birth rate for even years when few pinks are present could be the norm for the southern population with the situation improving with a “hypothesized positive effect of odd-year pink salmon since 1998,” the study said.

“As noted earlier, mortality of southern resident killer whales in odd years since 1998 has been 43 percent lower than in odd years during 1976−1997. However, at present we do not have a mechanistic explanation for how pink salmon would enhance southern resident killer whale foraging on Chinook salmon.”

The study suggests that given the seemingly obvious link between pinks and the whales further investigations should soon be undertaken.

“….A field study that quantifies foraging efficiency of southern resident killer whales during even versus odd years could be designed to test the two, pink-salmon hypotheses identified here,” it says. Modeling of southern resident killer whale demographics in relation to Chinook salmon and pink salmon abundance would also be informative.”

Such studies, the scientists said,  could help shed light on both the why of the death rate among older and younger whales, and the biennial drop in births.

Trophic cascades

The swings in pink numbers in the Salish Sea since 1976 are extreme with returns of only 100,000 to 400,000 in even years followed by odd year returns in the range of 16 to 19.6 million.

“Pink salmon have been shown to be very influential in ecosystems elsewhere in the North Pacific, where they initiate pelagic trophic cascades
and impact the growth and productivity of various other consumers, including several other species of salmon, other fishes, and seabirds in odd years of high abundance,” the study’s authors wrote.

Alaska’s chief commercial fisheries scientist has challenged that conclusion. Alaska Department of Fish and Game scientist Bill Templin in October dismissed a variety of studies dealing with trophic cascades. There are so many complicating interactions between the hundreds of species of North Pacific predator and prey interacting out of sight beneath the waves that it is impossible to draw conclusions as to why various bird or fish populations collapse, he said.

His comments came while the state Board of Fisheries was considering a proposal to freeze hatchery production of pink salmon in Alaska. The Board eventually voted against imposing a limit.

Alaska is a world leader in hatchery salmon production in the Pacific. It released almost 1.6 billion young fish last year, according to the North Pacific Anadromous Fish Commission, and that combined with about 375 million from hatcheries in the Lower 48 helped the U.S. claim the title of number one in the hatchery business. 

Former world leader Japan has scaled back its hatchery releases and is moving toward increased production of farmed salmon both offshore and on land.

In the definitive paper on North Pacific salmon populations, Ruggerone and Canadian scientist James Irvine in April reported that pink, chum and sockeye salmon populations in the Pacific are at never-before highs with pinks leading the way.

The scientists linked the increase to a warmer ocean, writing that  a “1977 regime shift benefited each species. During 1990–2015, pink salmon dominated adult abundance (67 percent of total) and biomass (48 percent), followed by chum salmon (20 percent, 35 percent) and sockeye Salmon (13 percent, 17 percent). Alaska produced approximately 39 percent of all pink salmon, 22 percent of chum salmon, and 69 percent of sockeye salmon, while Japan and Russia produced most of the remainder.”

The peer-reviewed study was published by the American Fisheries Society and added to the debate about just how far Alaska’s hatchery-driven, salmon-ranching program should go. The state long ago banned salmon farms and now tries to compete with the pen-raised fish that dominate the market by ranching salmon.

“Although production of natural‐origin salmon is currently high due to generally favorable ocean conditions in northern regions,” Ruggerone and Irvine wrote.  “Salmon abundance in large areas of Alaska (Prince William Sound and Southeast Alaska), Russia (Sakhalin and Kuril islands), Japan, and South Korea are dominated by hatchery salmon. During 1990–2015, hatchery salmon represented approximately 40 percent of the total biomass of adult and immature salmon in the ocean.”

A 2017 study of the Exxon Valdez Oil Spill (EVOS) that went looking for long-term environmental damage stumbled on evidence the Sound hatcheries were affecting runs of sockeye salmon to the Copper River just south of the Sound.

The peer-review study by a team of state, federal and univerity scientists who published at PLOS One “found no evidence supporting a negative EVOS impact on sockeye salmon or pink salmon productivity (and) weak evidence of a slightly positive EVOS signal on Copper River Chinook salmon productivity,” but “all sockeye salmon stocks examined exhibited a downward trend in productivity with increasing PWS hatchery pink salmon returns.

“While there was considerable variation in sockeye salmon productivity across the low- and mid-range of hatchery returns (0–30 million), productivity was particularly impacted at higher levels of hatchery returns.”

The latest study adds to the growing evidence that big swings in salmon abundance, whether natural or human driven, can have significant effects on more than just the salmon species enjoying a boom.














34 replies »

  1. James, your racist comment about Alaska Natives has no place in this discussion. Perhaps there is a bigoted forum someplace where such comments are appropriate, but hopefully it is not here.

      • Um, if you call MS-13 “immigrants”. So funny watching leftist spin.. Trump is 100% correct, they are rabid ANIMALS! You are sounding like that wing-nut Nancy Pelosi. Wonder if she will be flying the military B-757 home every weekend to see her family like she did the last time she was speaker..All complments of you Steve. Hmm, wonder what that cost the taxpayers, I mean suckas?

      • Bryan,
        List to his words for yourself.
        It is not OK to call human beings animals…
        This degrades human rights as a whole and further acts as a “dog whistle” to hate groups in America who carry out attacks on minorities and those who are most vulnerable.
        Although no one thinks an authoritarian regime can take hold in the U.S., ask yourself what other countries have political leaders who call people animals?
        Well, back in Germany in the 1930’s:
        “Animal functions similarly in this regard to the Nazi technical term “untermensch,” or underman, subhuman.”
        We also hear Israeli Politicians regularly refer to Palestinians in Gaza strip as “animals”.
        Neither example is good for the future of America or for the border with our neighbors in Mexico.
        And just so you know, I am all for deporting illegal immigrants, but not through the use of speech that degrades a nationality or specific race of Humans.
        History has proven this only leads to a further division and increased conflict…neither of which our country can afford at this time of “loyalty oaths” and forced allegiance to a dominant political party.

      • The animals thing is over blown. When I was a kid I took pride in being called an animal. Meant I was a tough as nails hard worker who could handle anything. Sure connotations can be twisted in whatever direction. I’m a civilized human animal! Just a thought. Hah !

      • Well Opinion,
        I guess we can conclude that James is well within his free speech rights to call Natives “environmental disasters”…
        I do think many situations out in the villages do fit this definition.
        From the honey bucket to annual killing and climate change to boot, much of village life today in Western Alaska resembles a lawless third world a 100 years ago.
        I only brought up the animal point since James was called a bigot for “environmental disasters” referring to natives in AK.
        Hell, I was called a bigot after I suggested a “man date”…but now I know the far right is extremely homophobic…go figure!

      • Perhaps we should all wear thicker skins ? No pun intended:) Yeah I saw that thread . It got a bit silly . ..

      • There was a Muppet named “Animal”, which makes the Muppet Show Racist, and since it aired on PBS then PBS must be Racist and since PBS is funded by the Government then the Government is Racist and since the Government gets its money from the Privately owned Federal Reserve Bank it is also Racist and since the Government pays the interest on borrowed money from the Federal Reserve Bank from the taxes on Corporations and Individuals ; then all those who pay taxes are Racist; and if you don’t pay taxes you receive entitlements from the Government which also makes you Racist; which means the whole damned country is hopelessly RACIST!

        There, I just took you down the mindhole of a Rabid Marxist Communist Leftest American Social Justice Myrmidon Lemming. Do you see now why they hate this country, its national anthem, its institutions, its people, the unborn, its history, its culture, and its President?

      • Sorry Steve if I hurt MS-13’s “Human Rights” but, they are worse than animals. They deserve to be shot on sight because they generally are violating some persons “Human Right” to life.
        Trump actually displays what made America great at one time. A time when men were men and didnt prance around in dresses screaming “you’re violating an illegal, murdering gangbanger’s Human Rights”. Steve, you are so biased against Trump you’d defend Hitler if it came down to it. Am amazing thing to watch.

      • Steve. What does POTUS comment have to do with this subject? Or do you feel the same way about native Americans as does James or SISU. I hope not.

      • Finally,
        My point is (and has been verified by several other comments) that as Opinion said:”Perhaps we should all wear thicker skins ?”…
        Not all critique of a group or culture can be immediately thought of as “racist” or “bigoted”…
        Hence, Trump’s “Animal” comment.
        This democracy was founded on critical thought and debate (at a time well before our polarized conflict during the Civil War).
        So as we see our liberties such as Free Speech and Freedom of the Press tested and government allegiance forced with Loyalty Oaths, we must continue to Express our opinions even if they may offend opposing sides.
        Currently nearly 30 states have anti BDS legislation on their books…any government employee or contractor found supporting the BDS movement against Israel will loose their job or contract.
        This amounts to loosing our right to “peaceful protest” in America which is supposed to be guaranteed in our constitution.
        So, you may continue to “thought police” this site, but if james said Rednecks are “environmental disasters” would that still make him a “racist” in your mind, or are the Natives in Alaska now like the Israelis…not open to critique in debate?

      • Steve,

        Let’s be honest here, you were called a bigot after you made a bigoted remark by trying to queer shame other posters you disagree with. You weren’t called a bigot after you suggested a “man date” as you are now claiming, you were called a bigot after you made blatantly bigoted remarks about two posters on here “hooking up” while on a “man date”. I get it man, you messed up, you made an obvious homophobic and bigoted statement…you probably even feel bad about it. Just don’t try to re-write history, own your mistake and move on, or own your bigoted words and move on, just stop lying about it. Coming from a bigoted homophobe, saying that “now I know the far right is extremely homophobic” goes beyond disingenuous, you sir have no shame.

        I honestly have no idea why you would even bring that up now, since you tucked tail for so long and avoided answering or responding to your slurring of others. Apparently you think it’s ok to queer shame people you disagree with and pretend like you didn’t and lie about it later.

      • Steve, I would like to apologize for misquoting you, as you didn’t say “hooking up” what you said was:

        Maybe U and Steve-O can hook up on a “man date”…
        U two seem to be “cut from the same cloth”.

        Perhaps, instead of calling other people you disagree with names you should try and make your point without denigrating others Steve, just a thought. You will probably think that me calling you a bigot and using what I just said against me would be a good idea, but I’ve only called you a bigot because of your comment that is so clearly bigoted. Had you owned up to your mistake like a man and dropped it then we wouldn’t be where we are now, rehashing your bigoted remark.

      • Mongo, and you forgot the racists and intolerant amongst us calling everybody else “racist and intolerant”. Leaves one scratching their head saying – “Animal Farm” (Sorry Steve, didn’t mean to come off as offensive using the word “Animal” again).

      • Bryan,
        No worries…
        Obviously some on this site do not have the “thick skins” that Opinion speaks of and instead of looking at the bigger picture they would rather remain “tongue tied” in the minutia…
        Such is life!

      • Steve,

        There’s a big difference between being thick skinned or getting tounge tied in the minutia and calling out those here, such as yourself, who make hypocritical and homophobic bigoted remarks. Now apparently you think you can call people names and they should just deal with it, oh yeah and “STFU” as you have said in the past.

      • Steve,

        Wow, you’ve really outdone yourself there. You queer shame people and then tell them they are homophobes, must be something in the chemtrails over your house. You’re a special kind of fella Steve.

      • Steve,

        I had to look up what BDS is since apparently only anti-Semites are in the know when it comes to that acronym. Anyways it stands for Boycott, Divestment, and Sanctions against Israel. Why am I not shocked that you are also an anti-Semite?

      • Steve O…
        Your ignorance to world affairs is obvious in every comment you make.
        I never said I supported BDS…
        And “anti Zionism” is NOT the same “anti Semitism” just so U know!
        I stated it is wrong to make it illegal in the U.S. to protest….hence the anti BDS legislation in place currently in America seems against our Constitution.
        Here is a recent article explaining the BDS movement…
        “Anti-Zionism Isn’t the Same as Anti-Semitism
        American Jews have nothing to fear from the new congressional critics of Israel.”

      • “…it’s entirely possible to oppose Jewish ethno-nationalism without being a bigot. Indeed, it’s increasingly absurd to treat the Israeli state as a stand-in for Jews writ large, given the way the current Israeli government has aligned itself with far-right European movements that have anti-Semitic roots”
        (NYT article)

      • Steve,

        It’s strange that you would think I should now what some random acronym stands for in a comment on an article about orcas and pink salmon.

        Here is another acronym for you, ADL that stands for the Anti-Defamation League and here is what they say about BDS:

        Is BDS Anti-Semitic?

        Many of the founding goals of the BDS movement, including denying the Jewish people the universal right of self-determination – along with many of the strategies employed in BDS campaigns are anti-Semitic. Many individuals involved in BDS campaigns are driven by opposition to Israel’s very existence as a Jewish state. Often time, BDS campaigns give rise to tensions in communities – particularly on college campuses – that can result in harassment or intimidation of Jews and Israel supporters, including overt anti-Semitic expression and acts. This dynamic can create an environment in which anti-Semitism can be express more freely.   

        And, all too often, BDS advocates employ anti-Semitic rhetoric and narratives to isolate and demonize Israel.

      • Well Steve O,
        U can see that any major political issue or movement, has supporters and then those looking to deface the cause (which is nothing against the Jewish religion or their right to a sovereign state…but it is everything about the loss of Palestinian’s land in the occupied territory)
        To show you that even some of the Jewish people support the Anti-Zionist movement against Israel, here is a video from Vice showing Jewish Rabbis protesting.
        They claim “Their job is to make people Think”.
        And that is my only point on the BDS movement….that those who wish to support it should not be punished by new legislation in our states…
        It destroys the 1st and 14th Ammendments which guarantees this right throughout all states.
        Loyalty oaths and anti protest legislation go against our Constitution.

      • It appears our Senators in Congress continue to bring anti BDS legislation to a vote while in the middle of the longest government shutdown?
        “That message makes a mockery of the constitutional principle that Americans are free to believe as they choose”
        – ACLU, on the Combating BDS Act
        “It’s absurd that the first bill during the shutdown is legislation which punishes Americans who exercise their constitutional right to engage in political activity,” Sanders wrote on Twitter on Monday.
        Newly elected Congresswoman Rashida Tlaib also criticised the proposal, which the Senate may vote on as early as Tuesday, urging politicians to remember that the US Constitution guarantees free speech.

  2. The best, and likely only, solution for bettering the environmental health of the oceans, and the planet, is a global pandemic that erradicates 90% of humans. Hopefully some terrorist organization has scientists at work on this. We all gotta go sometime. All at once would be a good thing for the environment.

  3. What info is missing here, is that the Southern resident killer whales, that inhabit WA West Coast, Puget Sound and waters in BC, were netted by PS commercial seine fishers, paid by SeaWorld, to live capture the whales. Over 300, either died, went missing or ended up in the pools of SeaWorld, during the ‘70s. The state of WA, stopped it finally in ‘76. The damage was already done! At what great cost? Orcas are social mammals, that need intimate interaction to survive. The loss of over 1/2 of it’s pods, has devastated these whales immensely, over the last 40 years, and they have never recovered.
    To make matters worse, due to declining chinook returns, over the last 20 years, Orcas have suffered even more, since chinook salmon, are their primary food source. From CA-BC, all pods are now endangered, and the data shows, that this is tied to the dismal chinook returns.
    The WDFW & Feds (think BPA), have been spending millions on chinook hatcheries on the Columbia River.
    The feasting Cormorants & CA sea lions appreciate the governments effort. We have interfered and the results are disastrous!
    The entire West Coast, from the bottom of CA to the Gulf of Alaska is in peril, declining chinook & sockeye returns are the new norm.
    Blame the lowly pink salmon, if you like, it will not matter in the long run. The once sustainable salmon returns on the West Coast are no longer sustainable. It is over and done! End of story!

    • James,
      Some good points there.
      Another concern for whales is that Japan has announced it will resume killing whales off of it’s coast in the Pacific and I wonder how that will further effect the species decline?
      I cannot believe we still allow natives to kill whales when the species faces extinction and there are other food sources like Caribou for them to eat.
      Just cause something was done in the past does not mean a “tradition” should be allowed to appease their elders.
      Another major concern of the Oceans right now is major Acidification taking place on a world wide scale.
      One side effect of burning fossil fuels that gets little attention.
      “Ocean acidification is the ongoing decrease in the pH of the Earth’s oceans, caused by the uptake of carbon dioxide from the atmosphere. Seawater is slightly basic, and ocean acidification involves a shift towards pH-neutral conditions rather than a transition to acidic conditions.”
      “Scientists estimate that carbon pollution is causing oceans to acidify faster than they have in 300 million years.”

      • Alaskan Natives are environmental disasters shielded by political correctness.

Leave a Reply